Apple’s upcoming iPhone 5 arrival will be anticipated by many. The arrival, however, will not be unchallenged as players like Samsung’s Galaxy S2 and Motorola’s Droid Bionic will keep a lookout.

Here are the reasons why Motorola Droid Bionic could be iPhone 5’s biggest rival this fall.

The biggest confusion with the Motorola smartphone is that whether it will arrive with 512 MB RAM, 2 GB ROM and 16 GB storage which was found in the original Motorola Droid Bionic showcased during the CES. The probability of Motorola Droid Bionic featuring 1 GB RAM is highly expected as the latest ad described Droid Bionic to be ferocious force and an all powerful unstoppable device.

There is a possibility of Apple iPhone 5 featuring a 768 MB RAM similar to HTC Sensation 4G. Apple, however, never reveals its RAM specification until a tear down of the device is done by tech journalists. Since iPhone 5 is expected to feature processor similar to iPad 2, the possibility of iPhone 5 running on 512 MB RAM cannot be ruled out.

Motorola Droid Bionic will arrive with an 8 MP 3264x2448 pixels camera along with autofocus, dual-LED flash, geo-tagging, face detection and image stabilization support. If 3D enhancement is making its way into Motorola Droid Bionic, then there is a possibility that the Droid Bionic will feature 1080p@24fps (2D) and 720p@30fps (3D).

The iPhone 5, however, according to a previous Bloomberg report, will have an 8 MP camera and will closely resemble the iPhone 4. 1080p video recording along with dual-LED flash is also expected. As leaked by Sony CEO Howard Stringer, iPhone 5 may also carry an HD FaceTime camera similar to those shipping with the current MacBook Pro lineup.

The Droid Bionic is rumored to arrive with a 4.3-inch 540x960 pixels (qHD) TFT capacitive touchscreen display. In case of iPhone 5, most rumors point towards 3.5-inch or 3.7-inch, 960x640 resolution at 312 ppi display screen.

iPhone 5 will come with Apple iPad 2’s processor. The smartphone will have 1 GHz dual-core ARM Cortex-A9 PowerVR SGX543MP2 GPU Apple A5 chipset processor. But, with iPad 2 featuring a 900 MHz processor, iPhone 5 can expect to get a 1.2 GHz processor to counter the 4G LTE support to some extent for speed enhancement.

According to GSMArena, the Droid Bionic has a dual-core 1GHz ARM Cortex-A9 processor, ULP GeForce GPU, Tegra 2 AP20H chipset. This is by no means less than what iPhone 5 has to offer.

There are very less possibilities that the iPhone 5 will arrive with 4G LTE as the phone must be modified to fit in the big LTE chip which contrasts with Apple planning to deliver a thinner and lighter device. The original Motorola Droid Bionic had 4.3-inch display and weighed 158 g. And with Apple iPhone 4 weighing just 137g, the probability of iPhone 5 crossing over 150 g is less likely.

This is one area where the Droid Bionic clearly outsmarts the iPhone 5. The speed of device may not matter for many users who use smartphones to check their email, browsing lightweight Websites, but it does make a big difference when transmitting large files, booking tickets online, bill payment, viewing complex sites or streaming video.

Droid Bionic’s input features include multi-touch input method, accelerometer sensor for UI auto-rotate, touch-sensitive controls, and proximity sensor for auto turn-off. Features like biometric fingerprint reader, MOTOBLUR UI with Live Widgets and Gorilla Glass display similar are also the strong points of the smartphone.

iPhone 5 is expected to closely resemble iPhone 4 and arrive with a scratch-resistant oleophobic surface, multi-touch input method, accelerometer sensor for auto-rotate, three-axis gyro sensor and proximity sensor for auto turn-off.

With iOS 5 and iPhone 5 releases expected to be on September, Apple iPhone 5 will come with iOS 5 operating system. Motorola Droid Bionic, on the other hand, will come with Android OS v2.3 (Gingerbread).

Droid Bionic is expected to have Wi-Fi 802.11 b/g/n, DLNA, Wi-Fi hotspot support whereas iPhone 5, comparatively, will have Wi-Fi 802.11 b/g/n, Wi-Fi hotspot support.

The Motorola-made smartphone, during its initial release in CES 2011, displayed a Li-Po 1930 mAh battery which is good enough to support the 4G LTE and dual core processor. The iPhone 5, in comparison, will closely resemble iPhone 4 and may arrive with Li-Po 1420mAh. An upgrade may also occur.